Observation of the cubic Rashba effect in a SrTiO$_{3}$ two-dimensional electron gas

Induced spin-orbit coupling effects at oxide interfaces, where $d$-orbitals form the conduction bands, are recently attracting much interest [1-4]. Here, we report magnetotransport of normally-off SrTiO$_{3}$ field-effect transistors with parylene gate insulator at a dilution refrigerator temperatures (50 mK - 1 K). An enlarged contribution of the weak antilocalization /weak localization (WL/WAL) effect in the magnetoconductance compared to that at 2 K [4] is used to analyze the Rashba effect in detail. It will be shown that a theoretical model with effective magnetic field configuration based on the cubic Rashba term perfectly matches the observed WL/WAL data.\\[4pt] [1] H. Nakamura \textit{et al}., Phys. Rev. B, \textbf{80}, 121308(R) (2009).\\[0pt] [2] M. Ben Shalom \textit{et al}., Phys. Rev. Lett. \textbf{104}, 126802 (2010). \\[0pt][3] A. D. Caviglia \textit{et al}., Phys. Rev. Lett. \textbf{104}, 126803 (2010).\\[0pt][4] H. Nakamura \textit{et al}., Phys. Rev. Lett., \textbf{108}, 206601 (2012).